The present invention relates to a multi-way input device which is used, for example, to move the cursor on the display screen of a computer to input thereto two-dimensional coordinates and, more particularly, to a multi-way input device using a strain-sensitive material.
FIG. 1 is a diagrammatic showing of a conventional device of this kind. Mounted on a mechanically strong, thin, flat, resilient metal plate 2 as of stainless steel is a joystick-like member (hereinafter referred to simply as a joystick) 3 with its downward protrusion 23a press-fitted in a centrally-disposed hole 23 of the thin metal plate 2 and swaged thereto. On the top surface of the resilient metal plate 2 there are formed four resistance films 14 at equiangular intervals about the hole 23. Underlying the resilient metal plate 2 is a mechanically strong, thick and flat mounting plate 4 as of stainless steel which has an opening 40. The resilient metal plate 2 has its marginal portion bonded or welded to the thick metal plate 4 in a manner to cover the opening 40. The joystick 3 is held coaxial with the opening 40. The resistance films 14 are connected to an external circuit via a flexible cable 120 fixedly attached to the top surface of the resilient metal plate 2.
The resistance films 14 are, for example, carbon-film resistors formed by screen printing. When the joystick 3 is tilted, two resistance films 14 in the direction of tilting and in the direction opposite thereto are deformed by a compressive force and a tensile force, respectively, and hence their resistance values change accordingly, indicating the direction of tilting of the joystick 3 and the extent how much it is being tilted.
With this conventional multi-way input device, since the mounting plate 4 and the resilient metal plate 2 are both flat or planar parts as mentioned above, bonding or welding of such flat plates is likely to cause a misalignment between their center axes. Some of multi-way input devices of this kind are very small, for example, measuring approximately 8 mm by 8 mm. Hence, even a slight misalignment between the mounting plate 4 and the resilient metal plate 2 affects the operation characteristics of such miniaturized multi-way input devices.
Since the multi-way input device is usually mounted, for example, in a keyboard switch with its mounting plate 4 attached to a flat or planar surface portion of a different object, it is inevitably necessary that the flexible cable 120 be connected to the joystick 3 side and that electric circuits including the resistance films 14 be formed over the exposed surface of the resilient metal plate 2. Accordingly, the electric circuits are always exposed to the outside, and hence they are susceptible to external noise.
At a joint 45 where the flexible cable 120 is fixedly secured to the surface of the resilient metal plate 2, scaling of or some other damages to printed wires is likely to occur.
Furthermore, the conventional multi-way input device involves a relatively many manufacturing steps of forming the resistance films 14 on the surface of the resilient metal plate 2, carrying out wiring for connecting the resistance films 14 to the flexible cable 120 and fixedly connecting the flexible cable 120 to the wiring.
It is therefore an object of the present invention to provide a multi-way input device which allows ease in the implementation of stable operation characteristic.
Another object of the present invention is to provide a multi-way input device which is insusceptible to damage.
Another object of the present invention is to provide a multi-way input device which is insusceptible to external noise.
Still another object of the present invention is to provide a multi-way input device which is easy to manufacture.
According to the present invention, there is provided a multi-way input device which comprises a pattern sheet, an actuation panel, a joystick, and a mounting plate and in which the pattern sheet has, as a one-piece structure of a flexible synthetic resin film, a strain sensor support portion and a wire lead-out portion. The strain sensor support portion has a plurality of strain sensors formed on its one side, and the wire lead-out portion has formed on one side thereof leads connected at one end to the strain sensors in a plane common therewith. The actuation panel is made of a thin sheet of resilient metal, which has an actuation-deformable portion and a plurality of fixing portions bent therefrom in the same direction. The strain sensor support portion is adhesive bonded on the side thereof opposite the strain sensors to the inside surface of the actuation-deformable portion on the side where the fixing portions protrude. The joystick is mounted protrusively on the actuation-deformable portion of the actuation panel at a position equidistant from the plurality of strain sensors. The actuation panel is fixed to the mounting plate through the plurality of fixing portions with the actuation-deformable part spaced away from the strain sensor support portion. The plurality of fixing portions may preferably be flat pieces. The strain sensor support portion has positioning edges for line contact with the flat surfaces of the fixing pieces of the actuation panel. The strain sensor support portion is positioned relative to the actuation-deformable portion with the positioning edges and the corresponding fixing pieces held in line contact with each other.
It is preferred that the actuation panel be formed by press working of a thin sheet of resilient and that the pattern sheet be formed by press cutting from a flexible synthetic resin film.